CONCURRENCY CONTROL
Concurrency control concurrent transaction execution ko manage karne ke liye use hota hain.
Concurrency control DBMS ke verious method se perform ho sakte hai jaise ki locking methods,timestamp methods ,validation bsd techniques and optimistic method
Basic rules for locking
1.Agar data item main read lock hai to, transaction bas use read kar sakta hai .par update nahi kar sakta.
2.Agar ek transcation main kisi data item main read lock hain ,to other transaction same data item main read loack laga sakta hai par write lock nahi laga sakta.
3.Agar data item main write lock hain to transcation usme read aur update dono operation kar sakta hain.
4.Agar ek transaction ke kisi data item main write lock hain ,to koi aur transcation same data item main read aur write lock nahi laga sakte.
Concurrency control concurrent transaction execution ko manage karne ke liye use hota hain.
Concurrency control DBMS ke verious method se perform ho sakte hai jaise ki locking methods,timestamp methods ,validation bsd techniques and optimistic method
Basic rules for locking
1.Agar data item main read lock hai to, transaction bas use read kar sakta hai .par update nahi kar sakta.
2.Agar ek transcation main kisi data item main read lock hain ,to other transaction same data item main read loack laga sakta hai par write lock nahi laga sakta.
3.Agar data item main write lock hain to transcation usme read aur update dono operation kar sakta hain.
4.Agar ek transaction ke kisi data item main write lock hain ,to koi aur transcation same data item main read aur write lock nahi laga sakte.
